Soft striped magnetic fluctuations competing with superconductivity in Fe1+x Te

Neutron spectroscopy is used to investigate the magnetic fluctuations in Fe1+x Te-a parent compound of chalcogenide superconductors. Incommensurate stripelike excitations soften with increased interstitial iron concentration. The energy crossover from incommensurate to stripy fluctuations defines an apparent hourglass dispersion. Application of sum rules of neutron scattering find that the integrated intensity is inconsistent with an S = 1 Fe2+ ground state and significantly less than S = 2 predicted from weak crystal field arguments pointing towards the Fe2+ being in a superposition of orbital states. The results suggest that a highly anisotropic order competes with superconductivity in chalcogenide systems.